1. Thermoresponsive behaviour of terpolymers containing poly(ethylene oxide), poly(2-ethyl-2-oxazoline) and poly(ε-caprolactone) blocks in aqueous solutions: an NMR study
- Author
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Svetlana Lukáš Petrova, Eliezer Jager, Jiri Spevacek, Rafał Konefał, and Svetlana Petrova
- Subjects
chemistry.chemical_classification ,Materials science ,Aqueous solution ,Polymers and Plastics ,Ethylene oxide ,Oxide ,Nanoparticle ,02 engineering and technology ,Polymer ,Atmospheric temperature range ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,chemistry ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Physical and Theoretical Chemistry ,0210 nano-technology ,Caprolactone - Abstract
1H NMR spectroscopy was used for the first time to investigate temperature behaviour of aqueous solutions of nanoparticles (NPs) prepared from linear and Y-shape terpolymers containing blocks of poly(ethylene oxide) (PEO), poly(2-ethyl-2-oxazoline) (PEtOx) and one linear or two star poly(e-caprolactone) (PCL) blocks with different length. Structural changes were characterized separately for all blocks in a temperature range 295–360 K, and a broad transition was observed at temperatures above ~320 K. The temperature behaviour of NPs solutions depends on polymer concentration and especially on terpolymer architecture. At the same time, NMR measurements revealed important role of PCL blocks in this behaviour. The spin-spin relaxation times T 2 of water (HDO) give information on the behaviour of water and on polymer-water interactions within the aforementioned temperature range. In NPs solutions of the linear copolymer, two types of water were detected at higher temperatures: “free” and “bound” water molecules with long and very short T 2 values, respectively. For NPs solution of non-linear terpolymer, two types of water were observed only for the highest used (1.5 wt%) polymer concentration.
- Published
- 2016
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